Prior Art
Covers suitable for temporary use in protecting grates in paint spray areas of a kind in which air is directed down through the grates in the floor area thereof to direct, remove, and collect excess spray paint therefrom, are known in the art.
The prior art is well summarized in U.S. Pat. No. 4,770,089, issued Sept. 13, 1988, the disclosure of which patent is referred to herein and by reference made a part hereof.
The present invention is of the same type as disclosed and claimed in U.S. Pat. No. 4,770,089, but provides a grate having certain unique structural characteristics and features which in turn provide certain operating advantages which did not characterize prior art structures, including the structure of U.S. Pat. No. 4,770,089.
In particular, the grate covers of that invention have been found in practice not to adhere adequately or securely to the grates intended to be covered thereby and, in fact, even when clips were provided, as disclosed in that previous patent, the tendency of the cover to lift off of the grate during use not only frustrated the objectives of the grate cover but indeed militated against its use in the paint spray area. Additionally, even when retaining clips were employed together with such prior-art structures, they existed as a separate unit and required separate and additional effort and care for their proper installation and still did not provide a fail-safe way to positively block lifting of the cover off of the grate, a feature which is provided according to the present invention by the employment of built-in protuberances on skirts which press against a portion of the underside of the grate cross members. In addition, in practice it has been found that the lower edges of the skirt members must be located below the bottom edges of the underlying grate blades to prevent undue collection of paint particles and the like, not only upon the lower edges of the grate blades and cross members, but also upon most of the grate proper, as well as upon the bottom surface of the grate cover, all of which again frustrated the objectives of the employment of the grate cover in the first place.
According to the present invention, the unsuggested structural characteristics and properties of the grate covers of the present invention eliminate the shortcomings of and objections to the prior-art devices in actual practice and provide a more environmentally-acceptable solution to the problem of the collection of paint spray particles and the like on paint spray booth grates as documented in U.S. Pat. No. 4,770,089.